The ruling coalition, For European Montenegro, is tipped to win Sunday's poll amid a wave of goodwill that followed the successful May 21 independence referendum.
Turnout was significantly lower than in May when 85 per cent of voters cast ballots.
According to the latest polls, the ruling coalition led by Milo Djukanovic, the veteran prime minister, could win support from 45 per cent of voters.
The main opposition bloc led by the Socialist People's Party of Predrag Bulatovic is expected to win 18 per cent of the vote, while a new political force, the Movement for Change, a non-governmental organisation-turned-party, can count on 16 per cent support, according to opinion polls.
Djukanovic's re-election bid has been boosted by divisions within the opposition, who have been unable to focus their attention on much-needed social, economic or political reforms for the Balkan country of 650,000 people.
The architect of Montenegro's drive for independence from Serbia, Djukanovic has argued that the country will now be able to pursue EU integration faster.
He has expressed hope that an "association and stabilisation agreement" can be signed by the end of the year, a first step towards joining the 25-member bloc.
"I expect these polls to be democratic and enable the election of a government able to respond to the demands Montenegro is facing," Djukanovic told reporters after casting his ballot.
485,000 people were eligible to elect the 81 members of parliament.
More that 2,000 observers, including 200 monitors from the Organisation for Security and Cooperation in Europe (OSCE) and other international watchdog groups, are monitoring the vote.